There are plenty of fish in the sea, right? While there may be plenty of fish, sometimes the aquatic creatures found in ecosystems aren’t necessarily the right kind. Invasive species are becoming a bigger and bigger problem in many areas, one of which is Lake Erie. And if these invasive species are allowed to continue, it might result in ecosystems devoid of any natural or useful wildlife, fisheries, or plant stocks.
One prime and notable example of this can be found in the lake trout populations of Lake Erie. A key predator in the aquatic ecosystem of Lake Erie, the lake trout is a long-living species that prefers cold, deep-water areas of Lake Erie. The lake trout have a slow reproduction rate, not reaching sexual maturity until 7 or 8 years of age (“Lake Trout,” n.d.) giving the lake trout the tendency of being a “K” species (a kind of species that tends to have longer life expectancies, produce less offspring, and be more dominant part in the food chain of an ecosystem; contrasts with “R” species that are found lower on the food chain, and produce much more offspring with lower life expectancies). This can be seen in Figure 1, where it is shown that lake trout are quite high on the Lake Erie food chain.
Figure 1: This diagram graphically illustrates the food chain throughout the Lake Erie aquatic ecosystem, showing what species show more “K-species” tendencies and what species show more “R-species” tendencies. (“LEfoodweb.pdf,” n.d.)
Species high on an ecosystem’s food chain play a very important role, both for the ecosystem and in human consumption. Throughout evolution, ecosystems have developed tenuous equilibriums between the “K” species and the “R” species, which allow the ecosystem to function sustainably. The loss of a species high on the food chain can have a wide-reaching effect more often than not leading to a multitude of problems, including biodiversity loss, (“Loss of Predators Impacts Food Chain,” n.d.). In regard to Lake Erie, the loss of the lake trout population would result in equilibrium turmoil, biodiversity loss, and many negative economic effects, one being a hit to the 4.5 billion dollar sport fishing industry found on Lake Erie (“Conserving Lake Erie and Our Great Lakes,” 2017).
However, as Figure 1 shows, there is a species that is higher than the lake trout, and many other of the dominant fish species on the food chain. Sea lampreys in the past century have had a devastating effect on many of the top species found in Lake Erie’s food chain which makes this species a perfect example of an invasive species that could have been prevented. The sea lamprey was brought into the ecosystem in the 1920s (Dec, n.d.) and even went as far as to almost eliminate the lake trout population in the 1950s and 60s(“LEfoodweb.pdf,” n.d.). The effects of this can be seen through data that organizations like the Great Lakes Fishery Commission collect. The data set displayed in Figure 2 is an excellent example of how organizations use data to see how the ecosystem is responding and what work still needs to be done. In this particle graphs, the number of wounds per 100 lake trout fish that are over 21 inches are tracked yearly and compared to the organization’s and ecosystem’s target goal (Dec, n.d.). This easily shows the great effect sea lampreys are still having on the lake trout populations and show that there is much work still needed to be done to bring the ecosystem back to its natural state. When the public realized the dire situation Lake Erie’s lake trout populations were in, organizations like Great Lakes Fishery Commission made lake trout restoration a major goal. They continue to accomplish this this through practices like regular lampricide treatments to attempt to control the sea lamprey populations and manual stocking of the lake trout populations (Dec, n.d.).
Figure 2: This graph illustrates data comparing the yearly numbers of lake trouts per 100 fish over 21 inches showing sea lamprey wounds versus the target goal. (Dec, n.d.)
The relationship between the Lake Erie lake trout and invasive sea lamprey specie is just one example of a worldwide issues. With the rise of human globalization there have been a dramatic rise in the number of invasive species and the negative consequences that can come with them. With many of these situations are caused by human actions, it will take a cumulative human effort to ensure that the ecosystems humans depend on for survival are kept intact, natural, and productive to ensure the health of our society and our Earth.
References
Conserving Lake Erie and Our Great Lakes. (2017, February 3). Retrieved June 14, 2019, from
Greater Cleveland Aquarium website:
http://greaterclevelandaquarium.com/conserving- lake-erie-and-our-great-lakes/
Dec, N. (n.d.). NYSDEC Lake Erie 2017 Annual Report. 80.
Lake Trout. (n.d.). Retrieved June 14th, 2019, from
http://wildlife.ohiodnr.gov/species-and-habitats/species-guide-index/fish/lake-trout
LEfoodweb.pdf. (n.d.). Retrieved June 14, 2019, from
https://www.glerl.noaa.gov/pubs/brochures/foodweb/LEfoodweb.pdf
Loss of Predators Impacts Food Chain. (n.d.). Retrieved June 14, 2019, from Voice of America
website: https://www.voanews.com/africa/loss-predators-impacts-food-chain